Method for transmitting acoustic signals from a memory or chip card, and card for implementing said method

ABSTRACT

A memory card or smart card for emitting sound signals. The card incorporates at least one controlling electronic micromodule which includes in particular processor circuits and a memory in which binary data is stored. An excitation device is connected to the micromodule to convert the binary data into sound signals. A vibrating membrane is connected to the excitation device to emit the sound signals. The vibrating mechanism is constituted by the card itself. Such a design is applicable in particular to transmitting binary data over a telephone line by acoustic coupling with a telephone.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method of emitting sound signals from amemory card or a smart card.

2. Discussion of the Background

It is now common practice to use a memory card or a smart card as a keyfor giving access to a service or as means for transferring data. Whenthis access or transfer is performed remotely, it is also known to useso-called “voice” cards where data is transmitted over a telephone lineby acoustic coupling with a telephone.

A voice card is described in particular in document EP-A-0 664 633 wheredata is converted into sound signals by means of a piezoelectrictransducer housed in the card, and those signals are emitted in voiceform by the transducer and are transmitted to the telephone line via themicrophone of the telephone. Emitting signals in “voice form” meansemitting at any frequency lying in the passband of the telephonenetwork.

Specifically, the user holds the telephone handset in one hand and thecard in the other hand and brings the card up to the microphone of thehandset, after which the user presses a key present on the card toactivate the process of transmitting in voice form data that is recordedin the card.

Transmitting data in that way is not without its problems, in particularconcerning manufacture of the card. The piezoelectric transducer must bereceived in a cavity that provides sufficient space to define anacoustic chamber. In spite of the small thickness of the card, 0.76 mmaccording to ISO standards, the dimensions of the cavity mustnevertheless be sufficient to obtain good performance from the acousticpoint of view, but that gives rise to a card that is fragile from themechanical point of view. It is therefore necessary to find a compromisewhich becomes increasingly difficult to achieve with reducing cardthickness. In addition, the acoustic chamber of the piezoelectrictransducer must communicate with the outside via holes formed in thecard. This means that the card is sensitive to constraints of theexternal environment, and in particular to moisture which can cause thepiezoelectric transducer to misfunction.

SUMMARY OF THE INVENTION

Starting from in-depth examination of this state of the art, and seekingto mitigate specifically the problems posed by manufacture whilecomplying with the thickness constraint imposed for this type of card,the Applicant has been led to design a new way of emitting sound whichconstitutes the subject matter of the present application.

To this end, the invention provides a method of emitting sound signalsfrom a memory card or a smart card, the method being characterized inthat it consists in using the card as a vibrating membrane, and insetting the card into vibration by means of an excitation device housedin the card for transforming it into a source that emits sound signals.

According to another characteristic of the invention, the methodconsists in using an excitation device which produces mechanicalvibration, and in housing the source inside the card in such a manner asto secure it thereto so that the mechanical vibration produced by theexcitation device is transmitted directly to the card to cause it tovibrate and cause it to emit sound signals.

Such a method of emitting sound signals presents the particularadvantage of facilitating the operations of manufacturing the card. Itis no longer necessary to provide an acoustic chamber in the cavitywhich receives the excitation device. This simplifies manufacture andalso improves performance both acoustically and mechanically.

Thus, and in spite of appearing paradoxical, the small thickness whichis a constraint in manufacturing a voice card of the prior art becomesan advantage in manufacturing a card that implements the method of theinvention. In other words, the thinner the card, the better theperformance of the method of the invention.

In addition, since the card is no longer pierced by holes which used tobe necessary for passing the sound wave, the emission method of theinvention can advantageously be implemented in a card which iswaterproof.

In general, a voice card is activated using a mechanical key integratedin the card.

According to another characteristic of the invention, the emissionmethod is activated from a touch-sensitive key, thereby making it easierto integrate such a key in a card of small thickness.

The invention also proposes a memory card or a smart card forimplementing the emission method of the invention, the cardincorporating at least one controlling electronic micromodule comprisingin particular processor circuits and a memory in which binary data isstored, an excitation device connected to the micromodule to convert thebinary data into sound signals, a vibrating membrane connected to theexcitation device to emit said sound signals, and an actuation key, thecard being characterized in that the vibrating membrane is constitutedby the card itself.

By way of example, the excitation device of the membrane-forming card isa device which produces mechanical vibration, such as a ceramic typepiezoelectric element, and which is secured to the card by beingembedded therein, for example. In which case, the piezoelectric elementand the card form an electro-acoustic transducer, the piezoelectricelement being excited by electrical signals delivered on the basis ofbinary data recorded in the card, for example.

Preferably, the excitation device of the membrane-forming card is placedin a corner of the card while enabling the card to vibrate substantiallyover its entire area.

This position presents the particular advantage of displacing theexcitation device away from the main twisting and bending axes of thecard, thus also enabling the card to satisfy ISO standards concerningthe mechanical stresses which the card must be capable of withstanding.

A card of the invention can be manufactured using conventional rollingor injection techniques, for example. To activate such a card, the userholds it between the fingers and activates the emission process by meansof a key of the card, as with a conventional voice card. However, it isimportant to observe that the mere fact of the user holding the cardbetween the fingers serves to amplify the vibration mode of the card.

According to another characteristic of the card of the invention, theactivation key is constituted by a touch-sensitive key which, comparedwith a mechanical key, presents the advantage of having no moving parts.

Like the card of the document cited in the introduction, such a card canbe used in particular for the purpose of emitting binary data in voiceform for transmission over a telephone line by acoustic coupling with atelephone. Under such circumstances, the card of the invention has theadvantage of not requiring accurate positioning relative to themicrophone of the telephone.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages, characteristics, and details of the invention appearfrom the description below given with reference to the accompanyingdrawing, given purely by way of example, and in which:

FIG. 1 is a diagrammatic view of a card implementing the emission methodof the invention;

FIG. 2 is a fragmentary section view on line II—II of FIG. 1; and

FIG. 3 is a plan view of the controlling electronic micromoduleintegrated in the card.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The memory card or smart card 1 shown in FIG. 1 incorporates at leastone controlling electronic micromodule MC, a battery P, and anexcitation device 5 designed to produce mechanical vibration.

The micromodule MC incorporates in particular a memory M of the EEPROMtype, processor circuits CT, an input/output interface I/O havingcontacts, and an activation key T for setting the excitation device 5into vibration. Two bidirectional electrical links L1 and L2 connect thememory M and the interface I/O respectively to the processor circuitsCT, and a one-way electrical link L3 connects the key T to the processorcircuits CT.

The battery P powers the processor circuits CT via an electrical linkL4.

The excitation device 5 is designed to produce mechanical vibrationwhich is transmitted directly to the card 1 so as to cause it to vibratelike a membrane. The excitation device 5 is connected via an electricallink L5 to the processor circuits CT of the micromodule MC.

The function of the processor circuits CT is to convert the binaryinformation stored in the memory M into sound signals. By way ofexample, the binary information can be subjected to frequency shiftkeying (FSK) type modulation. This modulation consists in generating acarrier wave at a frequency that differs depending on the logic state ofthe bit to be transmitted.

Such a card 1 can be manufactured by a conventional rolling method whichconsists in making a “sandwich” comprising a plurality of sheets ofplastics material that have been precut and that are stuck together soas to hold the various circuits of the card 1 captive between them.

By way of example and with reference to FIG. 2, the excitation device 5is constituted by a ceramic type piezoelectric element 5 a which issandwiched between two sheets 10 and 12 of plastics material that arestuck together. Specifically, the piezoelectric element 5 a is receivedin an opening 14 formed in an intermediate sheet 16 of plasticsmaterial. This opening 14 passes right through the sheet 16 and hasdimensions that match those of the piezoelectric element 5 a. Once thesheets 10, 12, and 16 have been assembled together with adhesive, thetwo faces of the piezoelectric element 5 a are in contact respectivelywith the two sheets 10 and 12, such that the piezoelectric element 5 ais thus mechanically secured to the card 1.

Advantageously, the excitation device 5 is positioned in a corner of thecard 1 for the reasons explained above.

In a preferred embodiment of the card 1, the activation key T isconstituted by a touch-sensitive key. More precisely, and with referenceto FIG. 3, the input/output interface I/O is constituted by the eightelectrical contacts referenced C1 to C8 in application of the ISOstandards, which contacts are flush with one of the faces of the card 1and selectively connected to the micromodule MC. The touch-sensitive keyT is constituted by an additional electrical contact C10 which is flushwith the same face of the card 1 and which is located in the immediatevicinity of the interface I/O. More precisely, the electrical contactC10 is situated close to electrical contact C5 which covers a largerarea than the other electrical contacts. The electrical contact C10 isconnected to the micromodule MC in such a manner that it suffices topress a finger, generally the thumb, simultaneously on the contact C5for the interface I/O and on the contact C10 of the key T in order toestablish an electrical link which activates the micromodule MC.

This key T may advantageously be associated with a circuit forvalidating activation of the card so as to avoid untimely operation inthe event of a finger touching the key, both during manufacturingoperations and while the card is being handled by its user.Specifically, such a validation circuit is incorporated in themicromodule MC and serves to detect voluntary action on the part of theuser on the key T prior to activating operation of the card.

Specifically, we consider an application in which the card 1 is used asa conventional voice card for emitting and transmitting sound signalsover a telephone line by acoustic coupling with the microphone of atelephone. The emitted sound signals correspond, for example, to abinary data sequence that is prerecorded in the memory of the card andwhich serves to identify the user.

The user takes hold of the card 1 between fingers pressed respectivelyagainst both of the main faces of the card 1, one of the user's fingersmaking electrical contact between the contact C5 of the input/outputinterface I/O and the contact C10 of the key T once the card 1 has beenpositioned physically close to the microphone of the telephone.

The emission process is then activated. In other words, the processorcircuits CT convert the binary data sequence taken from the memory Minto a sequence of sound signals which are applied to the excitationdevice 5. These sound signals serve to put the excitation device 5 intovibration, and the resulting vibrations are transmitted directly to thecard 1 which sets itself into vibration like a conventional membrane.The vibration mode of the card 1 is improved when the user holds thecard between the fingers. The card 1 is thus transformed into a sourcethat emits a sound wave representative of the binary data sequence takenfrom the memory M of the card 1. This sound wave is then transmittedover the telephone line via the microphone of the telephone.

A server connected to the telephone network thus receives a binary datasequence and can then trigger a unidirectional or bidirectionalidentification protocol for identifying the received sequence and forgiving the user access to a service provided by the server.

Naturally, such a voice card can be used as a conventional memory cardor smart card by being inserted in a reader which communicates therewithvia the input/output interface I/O.

What is claimed is:
 1. A method of emitting acoustic waves from a memorycard or a smart card, said card comprising a plurality of precut plasticsheets stacked and affixed so as to hold at least an electro-acoustictransducer having an excitation device, the method comprising the stepsof: producing mechanical vibration using the excitation device; andtransmitting the mechanical vibration directly to the card, therebycausing the card to vibrate and emit the acoustic waves.
 2. The methodaccording to claim 1, wherein the acoustic waves emitted by the card aretransmitted over a telephone line, by acoustic coupling of the card witha telephone, for remote transmission of binary data recorded in a memoryof the card.
 3. The method according to claim 1, wherein the emissionmethod is activated by a touch-sensitive key provided on the card. 4.The method according to claim 1, wherein the electro-acoustic transduceris excited by electrical signals delivered from binary signals stored inthe card.
 5. A card for implementing the method according to claim 1,wherein the card includes a controlling electronic micromodule havingprocessor circuits and a memory in which binary data is stored, andwherein the excitation device is connected to the micromodule to convertthe binary data into acoustic waves.
 6. The card according to claim 5,wherein the excitation device comprises a piezoelectric ceramic element.7. The card according to claim 6, further comprising a key situated onthe card and connected to the micromodule, said key being atouch-sensitive key to activate a transmission process.
 8. The cardaccording to claim 7, wherein the touch-sensitive key comprises a firstelectrical contact which is flush with a face of the card, wherein thecard has a second electrical contact of an input/output interface, thesecond electrical contact being selectively connected to the controllingmicromodule, and wherein the first electrical contact of the key ispositioned close to the second electrical contact of the card in such amanner as to enable a finger of the hand to press simultaneously againstboth the first and second electrical contacts to activate the controlmodule.
 9. The card according to claim 5, wherein the excitation deviceis positioned in a corner of the card.
 10. A method of emitting acousticwaves from a memory card or a smart card, said card comprising aplurality of precut plastic sheets stacked and affixed so as to hold atleast an electro-acoustic transducer having means for vibrating, themethod comprising the steps of: producing the mechanical vibration usingthe means for vibrating; transmitting the mechanical vibration directlyto the card, thereby causing the card to vibrate and emit the acousticwaves, and wherein the means for vibrating does not include an acousticchamber.
 11. The method according to claim 10, wherein the emissionmethod is activated by a touch-sensitive key provided on the card. 12.The method according to claim 10, wherein the electro-acoustictransducer is excited by electrical signals delivered from binarysignals stored in the card.
 13. The method according to claim 10,wherein the acoustic waves emitted by the card are transmitted over atelephone line, by acoustic coupling of the card with a telephone, forremote transmission of binary data recorded in memory of the card.
 14. Acard for implementing the method according to claim 10, wherein the cardincludes a controlling electronic micromodule having processor circuitsand a memory in which binary data is stored, and wherein means forvibrating is connected to the micromodule to convert the binary datainto acoustic waves.
 15. The card according to claim 14, wherein themeans for vibrating comprises a piezoelectric ceramic element.
 16. Thecard according to claim 15, further comprising a key situated on thecard and connected to the micromodule, said key being a touch-sensitivekey to activate a transmission process.
 17. The card according to claim16, wherein the touch-sensitive key comprises a first electrical contactwhich is flush with a face of the card, wherein the card has a secondelectrical contact of an input/output interface, the second electricalcontact being selectively connected to the controlling micromodule, andwherein in the first electrical contact of the key is positioned closeto the second electrical contact of the card in such a manner as toenable a finger of the hand to press simultaneously against both thefirst and second electrical contacts to activate the control module. 18.The card according to claim 14, wherein the means for vibrating ispositioned in a corner of the card.
 19. A memory card or a smart cardfor emitting acoustic waves, comprising: an electro-acoustic transducerhaving an excitation device for producing mechanical vibration; and aplurality of precut plastic sheets stacked and affixed so as to encloseat least the electro-acoustic transducer, the plurality of precutplastic sheets including a top sheet and a bottom sheet, and includingan intermediate sheet having an opening with dimensions matching thoseof the excitation device, wherein the excitation device is secured tothe card by arranging the excitation device within the opening of theintermediate sheet and by sandwiching the excitation device between thetop and bottom sheets, and wherein the mechanical vibration from theexcitation device is directly transmitted to the sheets, thereby causingthe card to vibrate and emit the acoustic waves.
 20. The memory card orsmart card of claim 19, wherein the excitation device comprises aceramic piezoelectric element.